dirty commit: can't get references to work correctly between any tables

app/presenters/dashboard/analyze/graph/students_by_grade.rb

@@ -0,0 +1,53 @@
+# frozen_string_literal: true
+
+module Analyze
+  module Graph
+    class StudentsByGrade
+      include Analyze::Graph::Column::Grade
+      attr_reader :grades
+
+      def initialize(grades:)
+        @grades = grades
+      end
+
+      def to_s
+        "Students by Grade"
+      end
+
+      def slug
+        "students-by-grade"
+      end
+
+      def columns
+        [].tap do |array|
+          grades.each do |grade|
+            array << column_for_grade_code(code: grade)
+          end
+          array << Analyze::Graph::Column::AllStudent
+        end
+      end
+
+      private
+
+      def column_for_grade_code(code:)
+        CFR[code]
+      end
+
+      CFR = {
+        0 => Zero,
+        1 => One,
+        2 => Two,
+        3 => Three,
+        4 => Four,
+        5 => Five,
+        6 => Six,
+        7 => Seven,
+        8 => Eight,
+        9 => Nine,
+        10 => Ten,
+        11 => Eleven,
+        12 => Twelve
+      }.freeze
+    end
+  end
+end